Sir Alex Ferguson has expressed his regret about letting Dutch defender Jaap Stam leave Manchester United back in 2001.

The imposing centre-half was a stalwart in the Red Devils’ defence since his arrival in 1998, but was sold to Lazio for a fee of £15.3million at the age of 29 after returning from injury.

Stam revealed in his autobiography that Ferguson had forced him to join the Serie A side in a conversation in his car at a petrol station.

Speaking in a preview for his exclusive interview for MUTV, Ferguson said ‘When I think of disappointments, obviously Jaap Stam was always a disappointment to me, I made a bad decision there.’

The Scot’s lack of judgement seemed to have gone into overdrive when he intercepted Stam on his way home from training, telling him to join Lazio as soon as possible.

Stam, in his autobiography serialised by the Sunday Mirror, said: ‘I soon realised the club wanted to get rid of me. They also needed the money. Very soon the book became an issue again,’ report the Sunday Mirror.

‘It led to a conflict between me and the manager.

‘One morning I told him what I thought and left the training ground on the spot. On the way home I received a phone call in my car from Fergie’s secretary.

‘She said that he wanted to speak to me. He came on the phone straightaway.

‘Ferguson said: “Where are you?” I said: “Close to my house, at a petrol station.” ‘Ferguson said: “Wait there!” He jumped in his car and came straight to me.

‘At the petrol station he parked his car and got in with me.

‘He told me that I had to be transferred. Then he said: “Will you please move to Lazio quickly?”

‘I agreed to do it. Right there and then. One quick conversation in my car at a petrol station in Manchester was enough for me to leave that big club.

‘When I think about it now, and I have never talked about it before, I find it unbelievable I let that, as a player, happen to me.’

Ferguson also said that current manager, the under-fire David Moyes should be more than happy if he brings a trophy to Old Trafford this season.

United have had a hugely disappointing start to their Premier League campaign, currently lying in eighth place, level with the likes of recently promoted Hull City.

While the title already seems to be slipping out of Moyes’ reach – eight points behind leaders Arsenal – Ferguson believes a trophy would be fine for the ex-Everton man.

‘For David, winning a trophy would be a fantastic achievement.

‘We must always remember the manager is the most important person in the club, whether its me, David Moyes or Matt Busby’

Ferguson’s full interview will be available on Saturday, the same day his former club take on Stoke at home.